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PHYLOGENETIC RELATIONSHIPS AMONG VIETNAMESE COCOA ACCESSIONS USING A NON-CODING REGION OF THE CHLOROPLAST DNA

LAM THI VIET HA^1,3,5*, DO TAN KHANG^2,3, HELENA EVERAERT^1,5, TRAN NHAN DUNG³,

PHAM HONG DUC PHUOC⁴, HA THANH TOAN³, KOEN DEWETTINCK¹ AND KATHY MESSENS⁵

¹ Laboratory of Food Technology and Engineering, Department of Food Safety and Food Quality,

Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium

² Graduate School of International Development and Cooperation, Hiroshima University,

Kagamiyama, Higashi-Hiroshima, 739-8529, Japan

³ Biotechnology Research and Development Institute, Cantho University, Campus II, 3/2 Street, Cantho city, Vietnam

⁴ Cocoa Research Institute, Nonglam University, Kha Van Can street, Hochiminh, Vietnam

⁵ Laboratory Agri Fing, Department of Applied Biosciences, Faculty of Bioscience Engineering,

Ghent University, Valentin Vaerwyckweg 1, 9000 Gent, Belgium

^*Corresponding author’s email: vietha.lamthi@ugent.be; Ph: 0032-9 264 62 65; Fax: 0032-9 264 62 22

Abstract

Cocoa cultivation has increased in tropical areas around the world, including Vietnam, due to the high demand of cocoa beans for chocolate production. The genetic diversity of cocoa genotypes is recognized to be complex, however, their phylogenetic relationships need to be clarified. The present study aimed to classify the cocoa genotypes, that are imported and cultivated in Vietnam, based on a chloroplast DNA region. Sixty-three Vietnamese Cocoa accessions were collected from different regions in Southern Vietnam. Their phylogenetic relationships were identified using the universal primers c-B49317 and d-A49855 from the chloroplast DNA region. The sequences were situated in the trnL intron genes which are identify the closest terrestrial plant species of the chloroplast genome. DNA sequences were determined and subjected to an analysis of the phylogenetic relationship using the maximum evolution method. The genetic analysis showed clustering of 63 cocoa accessions in three groups: the domestically cultivated Trinitario group, the Indigenous cultivars, and the cultivations from Peru. The analyzed sequencing data also illustrated that the TD accessions and CT accessions were related genetically closed. Based on those results the genetic relation between PA and NA accessions was established as the hybrid origins of the TD and CT accessions. Some foreign accessions, including UIT, SCA and IMC accessions were confirmed of their genetic relationship. The present study is the first report of phylogenetic relationships of Vietnamese cocoa collections. The cocoa program in Vietnam has been in development for thirty years.

Key words: Cocoa, Chloroplast, Non-coding region, Phylogeny, Theobroma cacao L.